Polychlorinated dibenzodioxins (PCDD) and dibenzofurans (PCDF) are persistent, toxic pollutants which pose a threat to both human health as well as the biosphere generally. These compounds, which may also be referred to as polyhalogenated planar polycyclic aromatics, are contaminants of herbicides, such as Agent Orange, and are generated as by-products in a variety of industrial chemical processes, as well as in the course of combustion or incineration of other polychlorinated organics, such as plastics and polychlorinated biphenyls (PCB). In view of the extensive use or occurrence of such processes, dioxins and dibenzofurans are widespread in the environment. Now that the harmful nature of these materials has become recognized, it has become a matter of high priority to address the issue of detection of these compounds. An important, nontrivial first step is to identify sites of pollution, which requires a simple, economical, and rapid test for detection of the presence of these compounds in samples taken from industrial processing, soils, human or animal tissues, as well as foodstuffs.
Polychlorinated dibenzodioxins (PCDDs) and dibenzofurans (PCDFs), and other chemicals formed during combustion and technical processes are extremely toxic and additionally environmentally stable. Efforts to monitor their formation and distribution have primarily been carried out by means of gas chromatography with mass spectroscopy, a relatively expensive procedure which involves elaborate sample preparation and the use of costly, complicated technical equipment. There is a need for a simpler and more economical analytical procedure for the substances mentioned, particularly those found in industrial samples which contain other substances which may interfere with the assay.
An important aspect of a desirable test procedure relates to specificity. There are a large number of congeners of both PCDDs and PCDFs, as well as PCBs, which vary in toxicity from very highly toxic to lesser toxicities, but which are also chemically similar to other, relatively harmless compounds. A second aspect of the problem is that the most toxic congener of these compounds in the environment, i.e., 2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD), is harmful in very small amounts, and is capable of being concentrated as it moves through food chains. Hence, a desirable test must be capable of detecting the presence of these harmful substances in very low concentrations in industrial process samples, environmental samples, human or animal tissues and foodstuffs. Chemical analysis of soil samples for contamination is also hampered by several other factors: (1) dioxins bind tightly to soil and show negligible solubility in water, and (2) the multiplicity of congeners and related chemical contaminants make quantitative assay by conventional gas chromatographic and mass spectrometric methods costly and time consuming. The costs and turn-around time of assays preclude detailed sampling of an area to determine the extent of contamination, and require the use of sophisticated centralized laboratories, unsuited for field monitoring of hazardous polychlorinated dibenzodioxins and dibenzofurans.
The present invention relates to a method of preparation of samples containing dioxins and related compounds such that they are suitable for assay by immunodiagnostic methods and a test kit which is useful for this procedure. Important members of the class of polyhalogenated polycyclic aromatics with a planar structure cited are dibenzodioxins, dibenzofurans and several polyhalogenated biphenyls. For purposes of simplification, the class of substances cited shall be referred to as dioxins or dioxin, when used as an adjective, as in dioxin fraction, in the following description.